Thanks for your reply David,

Here's what I tried...

I highlighted all the magazines and added a series WWJ. All show up now with that series as number 1 in the series.

Search field title (.*?)(\#)(\d+)(.*?)
Destination field series_index: \3
Test text: Woodworker's Journal #142 Jul-Aug 2000
Test result: 142 Jul-Aug 2000

With the error message: could not convert string to float: 142Jul-Aug 2000

It would seem that the search group (\d+) is somehow being expanded to include the following group (.*?)